Harnessing the Lysosomal Sorting Signals of the Cation-Independent Mannose-6-Phosphate Receptor for Targeted Degradation of Membrane Proteins

Membrane proteins are a crucial class of therapeutic targets that remain challenging to modulate using traditional occupancy-driven inhibition strategies or current proteolysis-targeting degradation approaches. Here, we report that the inherent endolysosomal sorting machinery can be harnessed for the targeted degradation of membrane proteins. A new degradation technique, termed signal-mediated lysosome-targeting chimeras (SignalTACs), was developed by genetically fusing the signaling motif from the cation-independent mannose-6-phosphate receptor (CI-M6PR) to a membrane protein binder. Antibody-based SignalTACs were constructed with the CI-M6PR signal peptides fused to the C-terminus of both heavy and light chains of IgG. We demonstrated the scope of this platform technology by degrading five pathogenesis-related membrane proteins, including HER2, EGFR, PD-L1, CD20, and CD71. Furthermore, two simplified constructs of SignalTACs, nanobody-based and peptide-based SignalTACs, were created and shown to promote the lysosomal degradation of target membrane proteins. Compared to the parent antibodies, SignalTACs exhibited significantly higher efficiency in inhibiting tumor cell growth both in vitro and in vivo. This work provides a simple, general, and robust strategy for degrading membrane proteins with molecular precision and may represent a powerful platform with broad research and therapeutic applications.

Antibody-Drug Conjugates Targeting the Human Epidermal Growth Factor Receptor Family in Cancers

Members of the human epidermal growth factor receptor (HER) family, which includes HER1 (also known as EGFR), HER2, HER3 and HER4, have played a central role in regulating cell proliferation, survival, differentiation and migration. The overexpression of the HER family has been recognized as one of the most common cellular dysregulation associated with a wide variety of tumor types. Antibody-drug conjugates (ADCs) represent a new and promising class of anticancer therapeutics that combine the cancer specificity of antibodies with cytotoxicity of chemotherapeutic drugs. Two HER2-directed ADCs, trastuzumane-emtansine (T-DM1) and trastuzumab-deruxtecan (DS-8201a), have been approved for HER2-positive metastatic breast cancer by the U.S. Food and Drug Administration (FDA) in 2013 and 2019, respectively. A third HER2-directed ADC, disitamab vedotin (RC48), has been approved for locally advanced or metastatic gastric or gastroesophageal junction cancer by the NMPA (National Medical Products Administration) of China in 2021. A total of 11 ADCs that target HER family receptors (EGFR, HER2 or HER3) are currently under clinical trials. In this review article, we summarize the three approved ADCs (T-DM1, DS-8201a and RC48), together with the investigational EGFR-directed ADCs (ABT-414, MRG003 and M1231), HER2-directed ADCs (SYD985, ARX-788, A166, MRG002, ALT-P7, GQ1001 and SBT6050) and HER3-directed ADC (U3-1402). Lastly, we discuss the major challenges associated with the development of ADCs, and highlight the possible future directions to tackle these challenges.

Longitudinal Study of SARS-CoV-2 Antibody Characteristics Using Label-Free Immunoassays

Introduction/Objective

Since the start of the COVID-19 pandemic, much research has focused on the kinetics and magnitude of humoral immune response. With the advantages of monitoring real-time immunoreactions, label-free immunoassay (LFIA) is becoming a powerful tool in serology studies. We have developed LFIAs to measure SARS- CoV-2 antibody avidity and neutralization activity in a cohort of COVID-19 patients and determine if they correlate with antibody concentration. Serial serum samples collected from mild to severe COVID-19 patients were measured out to 8 months post-symptom onset to determine the durability of the neutralizing antibody response.

Methods/Case Report

Based on thin-film interferometry technology, we established a label-free IgG avidity assay and a label-free surrogate virus neutralization test (LF-sVNT). For measurement, sensing probes pre-coated with receptor-binding domain (RBD) of SARS-CoV-2 spike protein are applied to serum samples containing SARS-CoV-2 antibodies. The label-free IgG avidity assay measures the binding strength between RBD and IgG under urea dissociation. The LF-sVNT analyzes the binding ability of RBD to ACE2 after neutralizing RBD with antibodies.

Results (if a Case Study enter NA)

IgG avidity indices and neutralizing antibody titers (IC50) were determined from serum samples (n=246) from COVID-19 patients (n=113). IgG concentrations were measured using a fluorescent immunoassay. The neutralizing antibody titers showed a weak correlation with IgG concentrations and no correlation with IgG avidity indices. Over the time course up to 8 months post-symptom onset, IgG concentrations and neutralizing antibody titers presented similar trends: an initial rise, plateau and then in some cases a gradual decline after 40 days. The IgG avidity indices, in the same cases, plateaued after the initial rise.

Conclusion

The results demonstrated that LFIA could be used an excellent solution in the determination of SARS- CoV-2 antibody characteristics. The study found that IgG concentration and neutralizing antibody titer declined over time, while IgG avidity index remained constant after reaching a plateau. The decline of antibody neutralization activity can be attributed to the reduction in antibody quantity rather than the deterioration of antibody quality, as measured by antibody avidity.

Micromagnetic simulation of microstructure effect for binary-main-phase Nd-Ce-Fe-B magnets

We investigate the magnetic properties of a chemically heterogeneous binary-main-phase (BMP) Nd-Ce-Fe-B magnet with a core-shell structure via micromagnetic simulation. It is found that the coercivity strongly depends on the shell thickness. The BMP magnet's coercivity initially increases and then decreases with increasing Nd-rich shell thickness, and so there is the optimal shell thickness which shows the maximum coercivity for any given Ce concentration. The simulation shows the significant difference in coercivity and maximum energy product between the BMP and single-main-phase magnets. Notably, the magnetization reversal mechanism of the BMP magnet is revealed in the simulation. Local reversals in the BMP magnet first occur in the Ce-rich shells, followed by the Nd-rich cores. Then, the magnetization in Ce-rich core/Nd-rich shell typed grains is switched after reversed magnetization of all the Nd-rich core/Ce-rich shell typed grains. The BMP magnet represents a further increased coercivity for a larger GB thickness, which can be well explained by a maximum stray field.

A15 EFFICACY AND SAFETY OF FILGOTINIB AS INDUCTION THERAPY FOR PATIENTS WITH MODERATELY TO SEVERELY ACTIVE ULCERATIVE COLITIS: RESULTS FROM THE PHASE 2B/3 SELECTION STUDY

Aims

The SELECTION (NCT02914522) Induction Studies evaluated the efficacy/safety of filgotinib (FIL), a preferential JAK1 inhibitor, as induction therapy for patients (pts) with moderately to severely active ulcerative colitis (UC) who were biologic-naïve but failed conventional therapy (Induction Study A) or failed prior biologics (Induction Study B).

Methods

Pts were randomized 2:2:1 to once–daily FIL 200mg, FIL 100mg or placebo (PBO). The primary (clinical remission), key secondary (Mayo Clinic Score [MCS] remission, endoscopic remission, and histologic remission), and exploratory endpoints (MCS response and endoscopic improvement) were assessed at Week 10.

Results

In both studies, baseline demographics and disease characteristics were similar across treatment groups. In Study A, 659 pts were randomized and treated. Baseline mean MCS was 8.6 and 56% had a Mayo endoscopic subscore (ES)=3. A significantly higher proportion of biologic-naïve pts on FIL 200mg achieved clinical remission vs PBO and all key secondary endpoints (Table). In Study B, 689 pts were randomized and treated. Baseline mean MCS was 9.3 and 78% had ES=3. Prior treatment failures were: anti-TNF (86%), vedolizumab (52%) and both (dual-refractory; 43%). A significantly higher proportion of biologic-experienced pts on FIL 200mg achieved clinical remission vs PBO. In Studies A and B, a greater proportion of pts on FIL 200 mg achieved an MCS response and endoscopic improvement vs PBO.

The rates of AEs, serious AEs and discontinuations due to AEs were similar across FIL and PBO groups during induction. In the PBO, FIL 100mg and FIL 200mg groups, serious infections occurred in 0.7%, 0.7% and 0.4% pts in Study A and 1.4%, 1.4% and 0.8% pts in Study B; H Zoster occurred in <1% in both groups for both cohorts.

Conclusions

SELECTION included a high proportion of dual-refractory pts, and pts with severe endoscopic disease. Both doses of FIL were well tolerated. Filgotinib 200mg was effective induction therapy for both biologic-naïve/-experienced pts with moderately to severely active UC.

Funding Agencies

None

A High-Resolution Liquid Chromatography-Mass Spectrometry Method for Identification of Toxic Natural Products in Clinical Cases

Introduction/Objective

Many natural products have biological effects on humans and animals. Poisoning caused by natural products is often found in clinical toxicology cases. Liquid chromatography-high-resolution-mass spectrometry (LC-HRMS) has recently emerged as a powerful analytical tool for large-scale target screening, and the application of LC-HRMS can be expanded to solve the clinical cases of natural product poisoning.

Methods

The LC-HRMS method is based on a spectral library of 121 natural products. The spectral library was constructed by analyzing standards either in a Q-TOF mass spectrometer (only MS2 spectra acquired) or in an Orbitrap Tribrid mass spectrometer (MS2 and MS3 spectra acquired).

Results

The LC-HRMS method was verified for the limit of detection (LOD) and matrix effects in both serum and urine matrices. For each compound, the LOD was evaluated from 1.0 ng/ml to 1000 ng/ml for urine samples and from 0.50 ng/ml to 500 ng/ml for serum samples. The matrix effects were determined at three concentration levels andranged from 30.4% to 123.5% for urine samples and from 23.4% to 132.9% for serum samples. The LC-HRMS method was successfully applied to identify the culprits in three clinical cases. In addition, the combined use of MS2 and MS3 spectra enhanced the accuracy of compound identification, in library search reducing the importance of retention time that varies among instruments and consumable lots. In Case 1, the patient presented with paresthesias, arrhythmias, and stiffened arms and legs. The toxic alkaloid aconitine was identified in the serum sample and the extract of herbs that the patient ingested. In Case 2, the patients presented with weakness, dizziness, and vomiting.

The symptoms were caused by mistakenly taking Nicotiana glauca leaves and the alkaloid anabasine was identified as the culprit. In Case 3, the patients were suspected of intoxicated by taking too much extract of lupini beans. The culprit alkaloids from lupini beans lupanine and sparteine were found in the serum samples.

Conclusion

The involvement of a toxicology laboratory with the capability to perform the LC-HRMS method and with experience in the investigation of undifferentiated cases provides a unique diagnostic advantage in cases where exposure to toxic substances is possible.

Adults with intellectual disabilities in China: comorbid psychiatric disorder and its association with health service utilisation

BACKGROUND

Adults with intellectual disabilities (ID) often have multiple comorbidities. Psychiatric disorders in this population have been poorly studied in developing countries. We aimed to investigate the prevalence of psychiatric disorders in adults with ID and whether comorbid psychiatric disorders were associated with health service utilisation.

METHODS

We obtained data from the Second National Sample Survey on Disability, conducted in 31 provinces of China and selected a subsample of 13 631 adults aged 18 years and above with ID. ID were defined by intelligence quotient score under 70, deficits in two or more adaptive behaviours and age of onset under 18 years. Psychiatric disorders were identified according to the International Statistical Classification of Diseases, Tenth Revision. Logistic regressions were used for data analyses.

RESULTS

The prevalence of psychiatric disorders in adults with ID was 16.7%. The most prevalent type of psychiatric disorder was dementia. Older adults, females, being minorities, urban residents, being literate, low-income groups and having severe ID, were associated with elevated risk of psychiatric disorder among adults with ID. Compared with individuals without psychiatric disorders, those with comorbid psychiatric disorders were more likely to use medical service and less likely to use rehabilitation service.

CONCLUSIONS

The prevalence of psychiatric disorder in adults with ID was strikingly higher than that in the general population. Health service utilisation among Chinese adults with ID remained a big challenge. There is a possibility of diagnostic overshadowing by local clinicians, which may have resulted in overdiagnosis of dementia and underdiagnosis of common mental disorders. This study informs further investigations regarding common mental disorders among people with ID and has implications for public health strategies and health policies to meet health service need for this population.

Effect of arousing stimuli on circulating corticosterone and the circadian rhythms of luteinizing hormone (LH) surges and locomotor activity in estradiol-treated ovariectomized (ovx+EB) Syrian hamsters

In most proestrous hamsters, novel wheel exposure phase advances activity rhythms and blocks the preovulatory LH surge, which occurs 2h earlier the next day. Because wheel immobilization does not prevent these effects we hypothesized that arousal alone blocks and phase advances the LH surge. Ovariectomized (ovx) hamsters received a jugular vein cannula and estradiol benzoate (EB) or vehicle was injected sc. The next day (Day 1), at zeitgeber time (ZT) 4-5 (ZT 12 = lights off), after obtaining a blood sample, each hamster was exposed to constant darkness (DD), and either remained in her home cage or was transferred to a new cage and exposed to a running wheel or a 2-hour arousal paradigm. Blood samples were obtained in dim red light and activity was recorded hourly until ~ZT 10-11 on Days 1 and 2. For the next 1-2 weeks, activity was monitored in DD. Plasma LH and corticosterone were assessed by RIA. Novel wheel exposure or arousal at ZT 4 greatly attenuated the Day 1 LH surge in ovx+EB hamsters, and phase advanced the Day 2 LH surge by about 2h. In proestrous hamsters, novel wheel exposure led to a prolonged (>2h) increase in corticosterone levels only when LH surges were blocked. Phase advances in activity rhythms were enhanced by estradiol and arousal. The results suggest that estradiol modulates the effectiveness of non-photic stimuli. The role of the increased activity of the hypothalamic-pituitary-adrenal axis associated with novel wheel-induced attenuation of LH surges in ovx+EB hamsters remains to be determined.

Endogenous estrogen metabolites as biomarkers for endometrial cancer via a novel method of liquid chromatography-mass spectrometry with hollow fiber liquid-phase microextraction

Increased levels of endogenous estrogens and their metabolites are well-known risk factors of endometrial cancer. The aim of this study was to quantitatively assess the potential for estrogen metabolites to serve as biomarkers of endometrial carcinogenesis. The following estrogen metabolites were evaluated: 2-hydroxyestradiol (2-OHE2), 2-hydroxyestrone (2-OHE1), 4-hydroxyestradiol (4-OHE2), 4-hydroxyestrone (4-OHE1), 16α-hydroxyestrone (16α-OHE1), 2-methoxyestradiol (2-MeOE2), and 2-methoxyestrone (2-MeOE1). The low content of estrogen metabolites in urine makes their measurement difficult. To address this issue, we developed a rapid, sensitive, specific, and accurate liquid chromatography-mass spectrometry (LC-MS) method, with hollow fiber liquid-phase micro-extraction (HF-LPME) for an enriched pretreatment of the sample and for the simultaneous quantification of estrogens and their metabolites in the urine samples of 23 post-menopausal female endometrial cancer patients and 23 post-menopausal healthy female controls. The levels of estrogens were found to differ between the endometrial cancer patients and the controls. The level of 4-OHE2 was elevated in patients compared with the controls, while the levels of 2-MeOE1 and 2-MeOE2 were reduced in the endometrial cancer group. The results of this study indicate an imbalance of estrogen metabolites in endometrial carcinogenesis, and that the elevation of 4-OHE2 may be used as a potential biomarker for the risk assessment of estrogen-induced endometrial cancer.

Abstract P6-06-42: Impact of molecular subtype on overall survival according to age in Korean women

Introduction: Breast cancer is a heterogeneous diseases, which is based on expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Using these factors, molecular subtype can be determined as luminal A, luminal B, HER2+, and TNBC. This is considered as an important prognostic factor. In breast cancer, age is the one of the important prognostic factors and prognosis is varied according to patients’ age. We performed this study to analyze the impact of molecular subtypes on prognosis of breast cancer according to patients’ age.

Patients and methods: We performed this study by using Korean Breast Cancer Society Registration Program data. Total 15,286 patients are included into this study, and they underwent surgery during the period Jan. 2001 to Dec. 2006. All patients were divided into two groups according to age (younger: age≤34, older: age≥35) and molecular subtypes were classified into four groups as follows: luminal A (ER+ and/or PR+, HER2-), luminal B (ER+ and/or PR+ HER2+), HER2+ (ER-, PR-, HER2+), and triple-negative (ER-, PR-, HER2-). We determined prognostic impact of molecular subtype on overall survivals (OS). Clinicopathologic results and OS were compared by chi-square test, Kaplan Meier test, and Cox's hazards model.

Results: Younger group more frequently had tumors with negative hormone receptor (ER-/PR-), worse prognostic factors and diagnosed with more advanced stage compared to older group. In univariate analysis, molecular subtype was not related with OS in younger group (p = 0.069), but not in older group (p<0.001). In multivariate analysis, molecular subtype was an independent prognostic factor for OS only in older group (p = 0.690 vs p<0.001).

Conclusion: In young breast cancer patients, less than 35 years, the impact of molecular subtypes on overall survival was not significant compared to other age group.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-42.

Influence of stereopsis and abnormal binocular vision on ocular and systemic discomfort while watching 3D television

PURPOSE

To evaluate the degree of three-dimensional (3D) perception and ocular and systemic discomfort in patients with abnormal binocular vision (ABV), and their relationship to stereoacuity while watching a 3D television (TV).

METHODS

Patients with strabismus, amblyopia, or anisometropia older than 9 years were recruited for the ABV group (98 subjects). Normal volunteers were enrolled in the control group (32 subjects). Best-corrected visual acuity, refractive errors, angle of strabismus, and stereoacuity were measured. After watching 3D TV for 20 min, a survey was conducted to evaluate the degree of 3D perception, and ocular and systemic discomfort while watching 3D TV.

RESULTS

One hundred and thirty subjects were enrolled in this study. The ABV group included 49 patients with strabismus, 22 with amblyopia, and 27 with anisometropia. The ABV group showed worse stereoacuity at near and distant fixation (P<0.001). Ocular and systemic discomfort was, however, not different between the two groups. Fifty-three subjects in the ABV group and all subjects in the control group showed good stereopsis (60 s of arc or better at near), and they reported more dizziness, headache, eye fatigue, and pain (P<0.05) than the other 45 subjects with decreased stereopsis. The subjects with good stereopsis in the ABV group felt more eye fatigue than those in the control group (P=0.031). The subjects with decreased stereopsis showed more difficulty with 3D perception (P<0.001).

CONCLUSIONS

The subjects with abnormal stereopsis showed decreased 3D perception while watching 3D TV. However, ocular and systemic discomfort was more closely related to better stereopsis.

Abstract P4-03-11: SUVmax of FDG-PET/CT is Associated with Chemotherapy Response Assay Test Results and Prognostic Factors in Breast Cancer Patients

Backgrounds:18F-fluorodeoxyglucose positron emission tomography with computed tomography (18F-FDG PET/CT) is widely used for cancer evaluation and there are several studies which suggested maximum standard uptake value (SUVmax) may reflect the cancer patients' prognosis. Adenosine triphosphate-based chemotherapy response assay (ATP-CRA) is commonly used as a chemosensitivity assay modality for the treatment of various cancers in clinical settings and there have been several studies on its usefulness in breast cancer. We previously reported chemosensitivity (ATP-CRA) results might reflect patients' prognosis. So we supposed that SUVmax could reflect chemosenitivity (ATP-CRA) results of patients, so performed this study to analyze the relationship between PET/CT SUVmax and chemosenstivity (ATP-CRA) results of these drugs. Furthermore, we evaluated prognostic factors for breast cancer according to SUVmax.

Materials and Methods: 102 breast cancer patients, who underwent PET/CT and chemosensitive (ATP-CRA) test between December 2010 and April 2012, were enrolled in this study. We analyzed, retrospectively, the correlation between SUVmax of PET/CT and chemosenitivity (ATP-CRA) results of doxorubicin/paclitaxel. SUVmax according to prognostic factors were also assessed.

Results: Chemosensitivity (ATP-CRA) results of doxorubicin and paclitaxel have significant positive correlation with SUVmax. Their correlation coefficient were 0.236 (p = 0.020) and 0.216 (p = 0.030), respectively. Patients with larger tumor size, higher histologic and nuclear grade, estrogen receptor negative, progesterone receptor negative, HER2 positive, and Ki67 positive (≥14%) have higher mean SUVmax values (p &lt; 0.05). In molecular subgroup analysis, triple negative group showed higher mean SUVmax values than luminal A group (p &lt; 0.001).

Conclusion: Higher SUVmax values of PET/CT is correlated with better chemosensitive (ATP-CRA) results of doxorubicin and paclitaxel, and poor prognostic factors of breast cancer. However, examination of additional cases might be needed.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-03-11.

Molecular cloning and characterization of an endogenous digestive β-glucosidase from the midgut of the fungus-growing termite Macrotermes barneyi

β-glucosidase from the midgut of the fungus-growing termite Macrotermes barneyi was first cloned and characterized to gain a better understanding of cellulolytic systems in fungus-growing termites. β-glucosidase activity was proven to present primarily in the midgut of M. barneyi and two β-glucosidases were partially purified from the midgut. Based on the N-terminus sequence of one of the β-glucosidases, a full-length cDNA fragment of 1708 bp was obtained. This sequence encodes a 493 amino acid protein belonging to glycoside hydrolase family 1. Quantitative real-time PCR analysis proved that the β-glucosidase gene was primarily expressed in the midgut. β-glucosidase was expressed heterologously and biochemically characterized. Results indicate that β-glucosidase is an endogenous, midgut-origin termite digestive enzyme. It may have applications in understanding the mechanism of lignocellulose degradation in fungus-growing termites.

Endostar, a recombined humanized endostatin, inhibits lymphangiogenesis and lymphatic metastasis of Lewis lung carcinoma xenograft in mice

OBJECTIVE

The aim of this study was to investigate the effects of Endostar, a recombined humanized endostatin, on lymphatic tumor growth, lymphangiogenesis and lymphatic metastasis of Lewis lung carcinoma (LLC) xenograft in mice.

METHODS

Lewis lung carcinoma xenografts were established in C57BL/6 mice by intravenous injection of 1 × 10(6) cells. Then the mice were assigned to two groups: the control group received caudal vein injections of 0.2 ml of 0.9% sodium chloride for 15 days, and the treatment group received 500 µg Endostar daily. Six weeks after LLC cell injection, the mice were sacrificed, and tumor multiplicity and tumor sizes were recorded. The expression of vascular endothelial growth factor C (VEGF-C) and podoplanin were observed by immunohistochemical staining.

RESULTS

Tumor numbers and sizes in the control group were significantly higher than those of the treatment group. The microlymphatic vessel density (MLVD) was 5.67 ± 1.57 in the treatment group, which was markedly lower than in the control mice (7.78 ± 1.56). Two lymph node metastases were observed in the treatment group, and eight in the control group. Lymphatic metastases were more frequent in the control group than in the treatment group. Expression of VEGF-C in the control group was significantly higher than that in the treatment group.

CONCLUSION

Endostar significantly inhibits the lymphatic tumor growth, lymphangiogenesis and lymphatic metastasis of Lewis lung carcinoma xenografts, and its inhibitory effect is due to its ability to partially regulate the tumor expression of VEGF-C.

Cleft size at the time of palate repair in complete unilateral cleft lip and palate as an indicator of maxillary growth

Cleft size at the time of palate repair might affect the difficulty of surgical repair and, thus, indirectly postoperative maxillary growth. This retrospective study aimed to determine whether a correlation existed between the cleft size at the time of palate repair and the growth of the maxilla. Maxillary dental casts of 39 infants with non-syndromic complete unilateral cleft lip and palate, taken at the time of palate repair, were used to measure cleft size. Cleft size was defined as the percentage of the total palatal area. The later growth of the maxilla was determined using lateral and postero-anterior cephalometric radiographs taken at 9 years of age. The Pearson correlation analysis was used for statistical analysis. The results showed negative correlations between cleft size and the maxillary length (PMP-ANS, PMP-A) and the maxillary protrusion (S-N-ANS, SNA). These data suggest that in patients with complete unilateral cleft lip and palate there is a significant correlation between the cleft size at the time of palate repair and the maxillary length and protrusion. Patients with a large cleft at the time of palate repair have a shorter and more retrusive maxilla than those with a small cleft by the age of 9 years.

TrkC binds to the type II TGF-beta receptor to suppress TGF-beta signaling

Growing evidence suggests that overexpression of TrkC, a member of the Trk family of neurotrophin receptors, could drive tumorigenesis, invasion and metastatic capability in cancer cells. However, relatively little is known about the mechanism of TrkC-mediated oncogenesis. The TrkC gene is a partner of the Tel-TrkC (ETV6-NTRK3) chimeric tyrosine kinase, a potent oncoprotein expressed in tumors derived from multiple cell lineages. Recently, we have shown that ETV6-NTRK3 suppresses transforming growth factor-beta (TGF-beta) signaling by directly binding to the type II TGF-beta receptor (TbetaRII). Here, we report that expression of TrkC also suppresses TGF-beta-induced Smad2/3 phosphorylation and transcriptional activation. Silencing TrkC expression by small interfering RNA in the highly metastatic 4T1 mammary tumor cell line expressing endogenous TrkC significantly enhanced TGF-beta-induced Smad2/3 phosphorylation and restored TGF-beta growth inhibitory activity. In contrast, expression of TrkC in 67NR cells, in which TrkC is not expressed, suppressed TGF-beta transcriptional activation. Moreover, we show that TrkC directly binds to the TbetaRII, thereby preventing it from interacting with the type I TGF-beta receptor (TbetaRI). These results indicate that TrkC is an inhibitor of TGF-beta tumor suppressor activity.

Identification and characterization of IS1112 and IS1113 insertion element sequences in Xanthomonas oryzae pv. oryzae

Two new insertion sequences (IS1112 and IS1113) were identified in the genome of Xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight of rice. Three copies of IS1112 were trapped, one containing 1052-bp and the other two with 1055-bp. They all have 25-bp imperfect inverted repeats with a 3-bp duplication at the site of insertion. They contain an open reading frame (ORF) of 317 and 318 amino acid residues, respectively. IS1113 is 1306-bp, contains 25-bp imperfect terminal inverted repeats, and is flanked by a 9-bp direct repeat at the site of insertion. It contains an ORF of 395 amino acid residues.

Mixture of N-carbamoyl-L-glutamate plus L-arginine can protect rats with liver cirrhosis from acute ammonia intoxication

BACKGROUND/AIMS

We earlier reported that N-carbamoyl-L-glutamate (CG) plus L-arginine (Arg) protected normal and 70% hepatectomized rats from intoxication by a lethal or sub-lethal dose of ammonium acetate, respectively. In the present study, the protective effect of these compounds on cirrhotic rats was assessed.

METHODS

CG plus Arg were administered prior to the injection of a sub-lethal dose of ammonium acetate into dimethylnitrosamine-induced cirrhotic rats. Control rats were given phosphate-buffered saline (PBS) instead of the mixture. The behavior of the rats was monitored until the time of sacrifice. Blood ammonia level, blood urea nitrogen (BUN) and liver carbamoylphosphate synthetase I (CPS I) activity were determined.

RESULTS

Pretreatment of rats with the mixture of CG plus Arg could significantly lower the blood ammonia level (P<0.05), increase the activity of CPS I (P<0.05), improve abnormal behavior associated with ammonia intoxication (P<0.05), and increase BUN (P<0.05), as compared with the PBS-injected control group. There were significantly close correlations between (1) the increase of CPS I activity; (2) the improvement of abnormal behavior; (3) the increase of BUN; and (4) the decrease of the blood ammonia level.

CONCLUSIONS

A mixture of CG plus Arg could protect rats with liver cirrhosis from acute ammonia intoxication.

Expression of hepatitis B virus X protein is closely correlated with the high periportal inflammatory activity of liver diseases

Hepatitis B virus X (HBx) protein is a multifunctional protein that exerts dual activity on cell proliferation and death. Although HBx is thought to be a major determinant that leads to hepatocellular carcinoma, its pathophysiological role in humans remains to be established. Attempts have been made to evaluate the role of HBx in liver specimens derived from patients with chronic B viral hepatitis and hepatocellular carcinoma. Among 25 paired liver specimens of hepatocellular carcinoma and corresponding nontumour liver tissues, HBx mRNA was hardly detected and was significantly lower than other HBV transcripts. An immunohistochemical study demonstrated that expression of HBx protein was also lower than other HBV gene products. Interestingly, however, expression of HBx protein changed with the progression of chronic hepatitis. HBx was expressed in 5.0% of patients with chronic hepatitis without cirrhosis but increased to 44.8% in chronic hepatitis with cirrhosis. In contrast, only one (3.7%) of 27 hepatocellular carcinomas showed HBx positivity whereas 29.6% of surrounding nontumour tissues was still HBx-positive. These results suggest that HBx may play a major role at the promotion stage of carcinogenesis. Noticeably, HBx-positive cells were preferentially localized in the periportal region of chronic hepatitis or periphery of cirrhotic nodules where high necroinflammatory activity was accompanied. We found a positive correlation between HBx expression and periportal inflammatory activity (P < 0.001). Thus, HBx may potentiate cell destruction and regeneration of liver that provide an opportunity for the accumulation of genetic mutations, which contribute to multistep hepatocarcinogenesis.

[Transitional pre-B-cell ALL]

An 18-month-old girl was referred to our hospital because of fever and pancytopenia. On admission, her bone marrow nuclear cell count was 45,000/microliter, being mostly blasts with cleaved nuclei. The leukemic cells were negative for peroxidase staining, expressed CD10, CD19, CD34 and sIg mu, and did not express sIg kappa and lambda, corresponding to a minor subpopulation of B cells known as transitional pre-B-cells (TPBs). Since TPB-ALL has been reported only infrequently, the incidence and clinical picture of this rare type of ALL are still uncertain. Extensive immunophenotypic studies to determine the expression of sIg mu, sIg kappa and lambda will provide accurate diagnosis, which is essential for effective management of this condition.

Identification of human antitumor cytotoxic T lymphocytes epitopes of recoverin, a cancer-associated retinopathy antigen, possibly related with a better prognosis in a paraneoplastic syndrome

Cancer-associated retinopathy (CAR) is a rare paraneoplastic syndrome, and the recoverin-specific autoantibody is suggested to contribute to the pathogenesis of retinopathy, including apoptosis of retinal cells. Because it is known that CAR(+) cancer patients have a preferable prognosis, we hypothesized that aberrantly expressed recoverin in cancer cells can become a target of cytotoxic T lymphocytes (CTL). Here we tested nine recoverin-derived HLA-A24-binding peptides for their capacity to elicit antitumor CTL. We observed recoverin-specific CTL responses in two HLA-A24(+) CAR(+) cancer patients. In addition, the CTL responses were obtained from three of ten CAR(-) cancer patients and two of six healthy individuals. The CTL precursor frequency of CAR(+) cancer patients and that of CAR(-) cancer patients was higher than that of healthy individuals. Of nine recoverin peptides, R49 (QFQSIYAKF), R49.2 (QFQSIYAKFF), and R64 (AYAQHVFRSF) were discovered to induce the peptide-specific CTL. Taken together, our present data suggest that peripheral activation of recoverin-specific antitumor CTL is likely to contribute to the preferable prognosis of CAR(+) cancer patients. Moreover, in cases other than CAR(+) cancer patients, recoverin may offer the opportunity to design epitope-based immunotherapeutic approaches for treating HLA-A24(+) cancer patients with a recoverin-expressing tumor.

Chemotherapeutic drug, adriamycin, restores the function of p53 protein in hepatitis B virus X (HBx) protein-expressing liver cells

Hepatitis B virus X (HBx) protein implicated in the development of liver cancer may inhibit the function of p53 tumor suppressor protein through cytoplasmic retention of p53 protein. Here, we attempt to investigate whether the functional inhibition of p53 protein by HBx protein is reversible. First, we provide the evidence for the association of endogenous p53 protein with HBx by co-immunoprecipitation in stable Chang cells that express HBx protein in an inducible manner (ChangX-34). By immunofluorescence microscopy, the major location of p53 protein of ChangX-34 cells was confirmed at the nuclear periphery as well as in the cytoplasm where HBx protein is mainly expressed. Surprisingly, anticancer drug, adriamycin induces the nuclear translocation of p53 protein sequestered in the cytoplasm. This change is accompanied by the restoration of p53 activity, which results in increased transcriptional activity at the p53-responsive DNA elements as well as increase of p21WAF1 mRNA expression. Further, we observed the induction of cell death and G1 arrest in these cells upon adriamycin treatment regardless of HBx expression. Together, we demonstrate that functional inhibition of p53 protein through its cytoplasmic retention by HBx protein is reversible. These results may be extended into other tumors of which p53 activity is modulated by viral oncoproteins.

In vitro and in vivo studies of AT-1362, a newly synthesized and orally active inhibitor of thrombin

AT-1362 was found to be a potent, selective, and competitive inhibitor of thrombin, with a Ki value of 6.7 nM. In a rat model of venous thrombosis induced by partial stasis and endothelial disruption, the ID(50) values (a dose required to obtain 50% inhibition of thrombus formation over each vehicle group) of AT-1362 and argatroban were 0.03 mg/kg i.v. plus 0.5 microg/kg/minute and 0. 13 mg/kg i.v. plus 8.7 microg/kg/minute, respectively, and the antithrombotic effect of AT-1362 without prolongation of bleeding time lasted for 2 hours and disappeared 4 hours after oral administration of 30 mg/kg. In the rat tail transection model, the BT(2) values (a dose causing two-fold prolongation of the bleeding time over each vehicle group) of AT-1362 and argatroban were 0.56 mg/kg i.v. plus 9.3 microg/kg/minute and 1.1 mg/kg i.v. plus 73.3 microg/kg/minute, respectively. The reduction of thrombus formation and the prolongation of bleeding time were correlated with an ex vivo activated partial thromboplastin time (APTT) for both drugs. AT-1362 at 0.3 mg/kg i.v. plus 5 microg/kg/minute and argatroban at 0.6 mg/kg i.v. plus 40 microg/kg/minute significantly (p<0.05 and p<0.01, respectively) improved the vessel patency in a FeCl(2)-induced carotid artery thrombosis model in rats. These results suggest that AT-1362 may be a potent antithrombotic agent for the treatment of thrombotic diseases.